function [] = chapter2_1run()

    function [f]=f(x,t)
        f = 0;
    end
    
    function [u]=u0(x)
        u = sin(x*pi);
    end
    
    function [a]=a(x,t)
        a=1/(pi)^2;
    end
    %u1 = Forward(@u0,@a,@f);
    %mesh(u1)
    %'press any key to continue'
    %pause on
    %pause
    t_max =10;
    a_max = 1/(pi)^2;
    u = ParabolicTheta(@u0,@a,a_max,@f,t_max,0.8);
    [s,l] = size(u);
    err = zeros(s,1);
    for i = 1:l
        for j =1 :s
            truth(j,i) = u0((j-1)/s)*exp(-(i-1)*t_max/l);
            err(j,i)=truth(j,i)-u(j,i);
        end
    end
    max(max(abs(err)))
    

    %mesh(truth);
    %'press anykey to continue'
    %pause
    mesh(u);    
end